This invention relates to an integrated circuit chip package (IC package) for logic circuits for use in information processing and communication systems.
IC packages for logic circuits have been developed in order to achieve higher speed devices in many fields, particularly, in an information processing system. As a result, IC packages carrying a plurality of IC chips on a substrate with a multilayer structure have been put into practical use. As examples of such IC packages, reference is made to a paper by Anthony Durniak in Electronics, entitled "IBM has a message: the 4300" on pp. 85-86, Feb. 15, 1979 and to FIG. 3 of Japanese Patent Application Disclosure No. 8096/1980 corresponding to U.S. Application No. 920,914 filed June 30, 1978. Each of these conventional IC chip packages comprises a plurality of chips mounted on a substrate with a multilayer structure and a plurality of input/output terminals for external connection provided on the rear of the substrate. With such a package, however, a plurality of signal lines must be disposed through the substrate for connection of the chips to the terminals, resulting in a complicated structure requiring an intricate manufacturing method. Also, since it is difficult to provide a structure to permit heat generated from the chips to be discharged from the under-surface of the substrate, a cooling mechanism must be equipped to discharge the heat from the upper surface. As a result, sufficient heat discharge cannot be achieved with the conventional IC package.